The role of the hippocampus in passive and active spatial learning.

Rats with lesions of the hippocampus or sham lesions were required in four experiments to escape from a square swimming pool by finding a submerged platform. Experiments 1 and 2 commenced with passive training in which rats were repeatedly placed on the platform in one corner-the correct corner-of a pool with distinctive walls. A test trial then revealed a strong preference for the correct corner in the sham but not the hippocampal group.